Two sodium iodide scintillators and a lithium-drifted germanium detector are used in the analysis by gamma-ray spectrometry of gaseous fission products obtained in sweep-capsule fission product release experiments. A description is given of the measurements of full-energy-peak efficiencies of the three detectors for the source geometries used in counting the fission product samples. Experimental efficiencies are compared with calculated efficiencies for one of the sodium iodide detectors. Measurements made of the resolutions obtained with each detector are also noted.